IQGAP1 binds B-Raf, MEK, and ERK and facilitates ERK activation by EGF (Roy et al., 2005). IQGAP1 regulates the phosphorylation of EGFr by ERK (Casar et al., 2009a). Other proteins that bind IQGAP1 include Cdc42 and Rac1, E-cadherin, β-catenin, calmodulin (White et al., 2009). IQGAP1 is over-expressed in some cancers, in some of these, high IQGAP1 levels is a sign of poor prognosis (Brown and Sacks, 2006; Jadeski et al., 2008). Blocking the interaction between IQGAP1 and ERK inhibits skin carcinogenesis driven by Ras-ERK pathway oncogenes (Jameson et al., 2013). The gene discussed is CDC42; the disease is cancer.